I use apple cider vinegar as a scalp rinse. I have a very sensitive scalp and it frequently is irritated. A quarter cup of ACV diluted with 3/4 cup water, dump over my head b/t shampoo and conditioner, let it sit for a few minutes (while I lather up, shave, whatever). It's worked wonders for my scalp. Braggs' works the best. My DH picked me up some regular store-brand because he didn't know where to find the Braggs (it's in the organics section). It's okay but not as effective as Braggs.
Incidentally, I first picked up Braggs' ACV on the advice of my vet who wanted me to use it (diluted) as a rinse for my rabbit's ears.
I never actually eat/drink the stuff. My bottle now lives in the bathroom.
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle